Rotary compressor



1919' s sheets-sheet 1 W. G. E. ROLAFF ROTARY COMPRESSORY Filed Dec. 19,

juz/anion" Mier. GZQJIVoZaF/l J2e/2&3.

Oct. 9, 1923.

W.- G. E: ROLAFF d ROTARY COMPRESSOR Filed Dep. 19. 1919 s sheets-sheet s @fz 4 A- 6 YY1 6 12;

7&3 v I 32 Patented Qct..- 9, 1923.

-Y 1,410,030 PATENT orifice.

WALTER G. E. ROLAFF, OF BELLEVILLE, ILLINOIS.

:ROTARY COMPRESSOR.

Application mea December 19, 1919. serial No. 345,995.

To all whom t mag/concern:

Be it known that I, IVALTER G. E. lioLAFF,

-a citizen of the United States, residing in the county oi St. Clair, city of Belleville, and State of Illinois, have invented new and useful' Improvements in Rotary Compressors, of which the following is a specification.

This invention relates to rotary machines such as the rotary compressors employed for compressing ammonia gas, air or other fluids.

The general object of the invention is to produce a rotary compressor, thel characteristics of which are lightness of weight and compactness combined with efficiency in operation; also to provide ample means .for relieving any excessive or dangerous pressure developed in the compressing chamber, and to provid'ean improved system of lubrication for the bearings and other parts of the compressor. Such compressors are frequently operated with a regulating system functioning in such a way that if the pressure in the storage reservoir to which the compressor delivers, drops below a given point, the motor and compressor start up automatically, and when theJ pressure rises .in the reservoir to a predetermined pressure,

the motor and compressor are automatically stopped. It is desirable that a compressor used in such a system should respond quickly to the conditions of the regulatingsystem, that is to say, it should promptly cease to deliver the compressed "fluid after the motoris shut off. It is also desirable that in Starting up the motor that drives the compressor, especially where the motor is of relatively low power for the compressor, the load should be placed on the compressor gradually. One of my objects has been to .provide a compressor ,which will substantially meet such requirements, that is to say, to provide a compressor which will op erate in praftice so that the pressureload will gradually comeA onto the compressor when the motor is starting up, and -which will also operate in such a way that when the compressor commences to stop, a very slight reduction in its speed will lresult in unloading the compressor in such a way as to stop or arrest the orcin `of the compressed fluid into the reservo1r;one of the objects has been to provide a construction tending to eect the separation ofthe lubrieating oil from the compressed'fiud.

simple and eilicient rotary compressor.

Further objects of the invention will appear hereinafter.

' The invention consists in the novel features, and in the general combination of parts to be `particularly described hereinafter, all of which contribute to produce preferred embodiment of my invention will be particularly described in the following I specification, while the broad scope of my invention will be pended claims.

In the drawing,

Figure 1 is a longitudinal vertical section through al compressor embodying my invention; this section is taken o'n the line 1-1 of Figure 3;.

Figure 2 isa vertical cross-section taken onthe line 2-2 of Figure 1;

Figure 3 is a vertical cross-section ltaken on lthe line 3-3 of Figure 1;

Figure 4 is a horizontal section broken away, and taken about on the line 4-4-o Figure 2;

Figure 5 is a longitudinal section through lthe outlet valve of Vthe compressor;

f pointed out in the apj Figure 6 is a cross-section through this l valve taken on the line 6 -6 of Figure '5 and Figure 7 is a horizontal section of the valve taken about on the line 7--7 of Figure 5.y p 1 f The adaptation of my invention described* below is applied to fluid compressin apparatus comprising a casing 1 including two heads 2, one of which carries a stuiiing box 3; these headsv are attached on the lends of the body 6 of the casing. The casing body 6 is formed below into a base 4 and 1s closed on its upper side by a cover plate 5.

The compressor which is carried within the casing is of rotary type and preferably constructed so that the cylinder of the compressor rotates with a drum lying-.within the. cylinder, and I provide means for cirl culatinga lubricating oil through the in.

terior ofthe compressor andv ast the bearings of the compressor. I a so provide a delivery-head which receives the compressed fluid from the compressor and this deliveryhead is preferably locatednear the axis of the shaft so that the oil is separated from 'which cylinder comprises an annulus or shell 13 to the ends of Which, heads 14 are att ached,-

I these heads le being provided with tubularv trunnions 15 which are rotatably mounted by means of ball-bearings 16 in the body section of the casing. l prefer to mount these ball-bearings 16 on two large eccentric heads 17, one off/Which is integral with a cylinden shell 18, other eccentric head being atbetween the drum and the shell.

taclied to shell by means et suitable screws ieee Fig. 2); the eccentric heads 17 and shell l constitute a large' adjusting eccentric 'lor regulating; the Contact between the drum 11 and cylinder-shell The eccentric heads are rotatably mounted in bores 2O of large diameterwhich are formed in annular flanges projecting- Ain from the in.u ner faces ot' the heads 2. These bores 20 are co-axial with each other and concentric to the axis of the shalt i The surface ot the drum 1l touches the inner sur-lace ot the shell' 13 of the cylinder (see Fig. 3). and as the drum is ot slightly smaller diameter than the shell lil, a crescent shapedcompression chamber 21 is formed The ends et this compression chamber are :formed by means of relief heads or floating heads 22 that lie against the end 'laces 23 et the drum and against the end faces 24 ot the shell 13, which faces are flush with each other. The relief heads 22 are tree to rotate but are held if in alignment by the real heads 1t Which engage'their edges. l provide means for admitting the fluid pressure to the outer sides of the floating heads to produce a force to hold them against the ends of the drum and' shell 13. r)This may be accomplished by developing a differential effective pressure on the opposite fac s of the floating heads. ln this Way, l p ovide for counterbalancing the force exerted by the Huid so that there is a slight excess of force on the outer side.

y For this purpose the middle portion of each end face of the drum is cut away or depressed so as to form a pocket or recess 25 in each end of 'the drum. The central portion of these l discs or floating heads 22 are formed with large openings 2 7 through which the shat't 8 passes.

interior ofthe cylinder, l.' provide the shaft 8 With a longitudinal bore, a portion 29 of Which constitutes an intake port or duct, and With this duct, communicates a plurality of orifices 30 which are formed through thelwall of the shaft and through a bushing a. The bore 31 of stuffing box 3 is pro- S5. The Huid is drawn alonzgT the bore 29 'toward the drum, and passes lthrough aport 39 (see Fig. 3) into a substantially radial inlet passage 40 which emerges on the cylindrical face ot the drum. This inlet passage lor the fluid is located `iust to the rear (with respect to the direction of rotation)l of a piston which is preferably in the form ot a radially disposed plate or blade 4l which slides infand ont in a guide slot 4:2 in the drum, so that it traverses the compressing" chamber 21 as the drum rotates. This pistou blade may be of any improved form that will insure efficient packing of its lines .et contact With the floating heads anl the shell 13. .The outer edge is held against the shellv 13 by centrifugal force as 'the drum and cylinder 12 rotate.

As the rotation takes place in the direction of the arrow indicated in Figure the fluid, such as air or ammonia. is conipressed in the forward'portion 2l ot the compression chamber 21 which is toi-ward oi the piston blade 41, and the compressed fluid finds outlet through an outlet valve 43 ot multiple port type, the details of which are illustrated in `Figures 5 to '7. This valve is located back ot a longitudinal slot el which is an outlet in the Wall of the drum, and consists ot' a substantially circular bloei: 45, (see Figi. 6) having four ducts 46 which communicate with a valve-chamber 47. '.lliis Valve-chamber is located directly hack ota plurality of valveopenings 45E-which are normally closed by an elongated valve in the form of a plate 49 lying in the valvechamber t7 and held against the inner ends ot the Tvalve-openings 48 by means of a leaf .springl 50. `This Y device operates as a multiple portcheck-valve.

New, When the pressure rises in the por tion 21aof the compression chamber 2l, forward of this piston plate 41, this valve plate 49 opens and the fluid passes through the ducts or ports 46. haelt into a lar Ae passage 51 (see Fig'. 3) which is forme longi tudinally in. the drum. Any suitable means may be provided for conducting this compressed fluid awayH `from the compressor which is consistent v'itha. construction operating in such a Way as to ladmit the fluid to the outer sides of the doatinggheads. l provide escape passages 33 beyond the relief heads into which the compressed duid may escape past the heads it the pressure yvided with paekin rings 32 on each side of l.the bushing 30, t ie .packing rings and the llO lmay operate as ordinary receivers for thev sure.

51 emerges on the end faces delivering the within the cylinder 12 should rise suddenly to a dangerous point, and these passages 33 compressed fluid. Thesereceivers or passages extend over the outer faces of the relief heads so as to subject them to pres- In the present instance, the assage compressed fluid through the` aforesaid openings 27 into the relief passages or escape passages 33 and through the tubular trunnions l15. ,The chambers around the outer sides of the' floating heads, therefore constitute receivers for the iluidun'der pressure, The outer sides of the floating heads 22 are exposed to this fluid pressure which is Adeveloped -by the compressor. .'On account of the recesses 25, it will be evident that the fluidv pressure is admitted to the inner'faces as well as the outer faces of these heads and the force on the opposite faces is nearlybalanced. -There is, however, an excess of total pressure or force developed .on the outer sides of the heads by reason of the fact that the areas opposite the faces 23 and 24 of the drum and shell`13'are not balanced. Hence, it will be seen that these heads 22 'are held yieldingly against the ends of the drum by reason of the excess of effective area exposed .to the fluid pressure on thev 1 spiral springs 52 which are d1s osed in pockets 53 on the inner faces of t e heads 14. (See Fi'g. 1.)

The rotary parts within the compressor throw olf the lubricating oil by centrifugal force. I provide means substantially in the plane of rotation of these parts for catching the oil, and I also provide means for returning this oil tol the compressor. v'This means 1s preferably so organized as to e'ect the gradual loading of the compressor by by-passing the compressed lfluid with the lubricating oil when the compressor starts up. In this way I effect; the gradual choking of the by-pass when the compressor starts up. For this purpose, the interior of the casing is provided with means for catching the oil which may consist of a basin 57 l(see Figs. 2 and 4) formed on one of the heads 2, and in which the oil accumulates as it is thrown out from the shaft and adja' cent bearings. When thel machine is in operation, a bath of lubricating oil accumul lates in the .basin 57, filling the4 same. In

.order to return this lubricating voil to, the

intake ports 30, I provide a by-pass 59 comprising/ a short vertical pipe 60 in which is connected a sight-feed 61, Vthrough which the oil passes downwardly,l lthe lower end of` the pi e being connected. to the intake pipe 28. A valve 63a is provided for regulat' 63 forming-part of the by-'pass connects to Ithe basin 57 through an outlet 64 inthe side ofthe basin and the relation of this outlet to the overflow edge 65 of the basin is important, vas effecting the mode vof operation o f the compressor, as will appear hereinafter.

yI shall now describe the purpose of the eccentric heads 17 and the eccentric .shell 18. Referring especially to Figure 3, it is evident ythat by reason of thisneccentric mountingfor the cylinder, if the eccentric shell 18 is rot-ated in the proper direction, the shell 13 of the cylinder 12 can be forced against the face of the drum. I Aprovide means yieldingly tending to rotate the eccentric shell, for this purpose. The construction employed includes a coiledspring 66, one end of which is anchored at 67 at the side of the ring and the other end of which is attached to a nut 68'on the end of'an adjusting stem 69, which is rotatably mount'- ed vin a stuiiing box 70 mounted in an inclined position in the upper portion of the main section6 of the casing. By rotating this stem 69 by means of a wrench applied to its squared end, the tensionof the spring .can be adjusted; in other words, the pressure of the shell 13l against the drum can be adjusted. In practice, the shell should be held against the drum with just sufficient pressure to insure that the* cylinder 12 will rotate in unison with the drum. This avoids any friction, except rolling friction, 'between the drum and the shell 13. The intake pipe 28 may be provided with a small check-valve. 28a which opens inwardly and prevents a back flow of air from the machine when it4 stops.

In order to keep the compressor and its casing cool, I provide a suitable watercir culation system. For this purpose the mainpose I deliver the compresse-d fluid about on lthe'axis of the shaft 8. To accomplish this,

I use one end of the bore of the shaft as an Aoutlet duct 29h, and separate it from rhein,

let duct 29a. by suitable means'such asa plug 75. The receiving chamber 33 v in the adjacent head has outlet ports 6 which let the compressed fluid escape intel the duct 29". In order to assist in directing the/fluidv through these ports Iv providev a baillel plate 77 lthat covers the adjacent ball bearing 9.

'The dir t 29b is quite free fromoil because it -I 'is on the jaxis of revolution, the oil being lao - torce.

thrown away from this point by centrifugal Port or duct 29b carries the fluid to the end of the shaft and delivers it into a deliveryhe-ad or elbow 7 8 from which a pipe leads to a reservoir. A small drain-duct 79 is provided in this elbow through which any oil accumulating in the elbow may drain 'back into the casing.

rli`he plug 75 is preferably constructed to operate as a safety device.. To accomplish this the plug carries a disc 80 of sheet lead Vor other suitable material that will blow out with reasonable accuracy at a predetermined lthe bottom of the basin.

pressure.

A suitable removal drain plug 81 may be provided in one ot the heads 2 on a level with the bottom of the body section t5 of the casing.

l shall now describe the mode of operation of the entire compressing apparatus.

Illhe shaft 8 is rotated by any suit-able means, thereb rotating the drum 11 and the cylinder 12 o the compressor in unison. As.

the cylinder and drum rotate, substantially the same cycle, or relative movement occurs as though the drum were rolling around the interior of a lined cylinder. The result of this is that the air 4or ammonia, which is in advance of the piston el, is compressed and forced out through the multiple valve and through the passage 5l. At each rotation, fluid to be compressed is drawn in from the chamber 26 through the ports or orilces 80 into the intake duct 29*L in the shaft, and` thence through the port 39, and passage 40 into the compression chamber 21 behind the piston t1. As the compressed iiuid passes out of the ends el the port 51, it passes over and carries oil to the ball bearings.. The

compressor should be very liberallysupplied with oil. While the compressor is 1n operation, the lubricating oil flows continuously through the pipe to the pipe 28 and thence through ports 30, and Hows in with the inducted fluid which is to be compressed,

so that it passes bach into the compressor and into the com ression chamber 21. rllhis `oil thoroughly lu ricates the interior of the cylinder and the rubbing faces` of the floating heads, the drum, and the shell 13, not only reducing friction, but assisting in making air-tight contact points between these parts. As the oil is carried into the bearings it 'also keeps them thoroughly lubricated. Furthermore, `as the supply of oil is liberal, a quantityo the oil is constantly' being thrown up by centrifugal force so as to be caught in the basin 57. llt will Vbe noted that the upper edge of the outlet 6d is slightly below the level ot the overow edge of the basin; andthe lower edge `or the outlet tl-fis disposed above A When the machine'is not in operation, the level of the oil is even with the lower edge of the outlet tt i hermoso because the remainder of the oil will have gravitated through the by-pass 59 down into the bore of the shaft 8, and 'possibly down intothe compression chamber 2l, if the drum has happened to` stop in the position in which it is illustrated in Figure 3. With the level of the oil in the basin 57 at the lower edge of theoutlet 64, it will be evident that when the ycompressor starts up, the Huid passing through the compressor will move out into the receiving chambers 33 without developing'any pressure because it will find unrestricted outlet through bearings 16, shell 18 and the'byepass 59 ift the valve 63 is open; and hence, -when theV machine starts up, the duid to be compressed is simply churnedsa around Vthrough the compressor and through the by-pass, that is to say, it circulates without developing any pressure.

As the speed ot the compressor lncreases, however, the oil accumulates 1n the basin 57 and tends more and more to-ill and choke the by-pass 59. When the level of the oil nally rises to about level with the upper edge of the outlet 6d, the by-pass will be completely choked with oil, hence the air or ammonia being compressed will then be excluded from the by-pass.I After this moment' arrives, real compression of the fluid will begin and the pressure in the head 78 will rise rapidly until it arrives at the pressure existing in the reservoir to which it is connected; then the valve (not illus-y trafted) to the reservoir will open and lthe air or ammonia gas will flow into the reservoir. Alfter pressure lhas been developed in the delivery head, of course the circulation of the oil is accelerated through the bypass on account of the pressure on thesurface ot the oil in the basin 57. rlhe valve 63a enables the operation of the compressor to be nicely regula/ted.

By reason of the tact that' the ley-pass chokes gradually in the manner described, the load will come very gradually upon the compressor. While this matte'ris kof small importance' in smallmachines, it is of more importance in the larger types because it allows time for the motor to attain substantially its normal speed before the actual compression begins.

When the motor is stopped in order to stop the operation of the compressor, the

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Y floating .heads and'these parts which would cause fr1ction. There is, of course, a slight rubbing movement because the drum and the cylinder. do not rotate at the same angular velocity., 4

Any sudden pressure developing in the cylmder and which is not taken care of by the valve 43 will be relieved at the floating heads. Such a sudden high pressure may arise by the sudden vaporizing ofammonia coming into the cylinder. It is obvious that the relief-feature of the floating heads could be secured by the use of a single floating head.

Certain features described and shown in the drawing in this application are also shown in applicants co-pending application Ser. No. 222,126 for rotary compressor, filed November 19, 1919, and are covered by claims in that application.

It is understood that the embodiment of the invention described herein is -only one.

of the manyembodiments'my invention may take, and I do not wish to be limited in the practice of my invention nor in my claims, to the particular embodiment set forth.

What I claim is: l1. In a fluid compressing apparatus, the combination of a cylinder-shell, a .rotary drum eccentrically \mounted inthe shell,

i and co-operating therewith to form a comcombination of a cylinder-shell, a rotary pression. chamber, relief heads disposed against the ends of the drum and shell, and constituting the end walls of the compression chamber, and means for admitting the fluid pressure to the outer sides of the relief heads to hold the same against the ends of the cylinder and drum.

2. In a fluid compressing apparatus, the

drum eccentrically mounted within the Shell and co-operating therewith to form a compression chamber, relief heads disposed respectively against the ends of the drum and shell, and constituting the end Walls of the compression chamber, and means for admitting the fluid p essure to the inner sides and the outer ides of `the relief heads,

the area exposed to the fluid pressure on the outer sides of the heads being slightly greater than the exposed area on the inner sides ofthe heads whereby the heads are pressed by a relativelyismall force aga-inst the ends of the drum and-shell.

3. In a fluid compressing apparatus, the combination of a cylinder-shell, a rotary drumv eccentrically mounted in the shell and (1o-operating therewithto form a compression chamber, a relief head disposed against each end of the drum. and shell, said relief heads constituting the end walls of the com- YYpression chamber, means for admitting the fluid under 'pressure to thev outer sides of the relief heads, each end of said drum having a recess formedtherein to which the fluid pressure is admittedto kpartially counterbalance thev fluid. pressure on the outer sides of the heads, the area exposed to the fluid pressure on the outer sides of the heads being slightly in excess of the exposed areaA on the inner sides of the heads, thereby producing aslight excess'of force ,on the outer sides of the heads to holdthe same against Athe ends of the shell and drum which lwill ypermit the'heads tov move outwardlyl ifa dangerous pressure occurs within the cyl-l inder.

. 4. In a fluid compressing apparatus,v the combination of a cylinder-shell, a rotary' operating to move outwardly if a sudden increase in pressure should occur in the cyl-v v n connection therebetween, saidl -relief head 4 inder, and thereby relieve the pressure within the cylinder.

5. In a rotary compressor, the combination of a cylinder, a rotary drum eccentrically mounted therein, and co-operating with the cylinder to form a com ression chamber, means for admitting a flui to said compression chamber, floating heads disposed against the ends of the drum and constituting the end walls of the compression chamber, escape passages beyond'. said floating heads, and means for yieldlpgly holding the floatino` heads against the ends of the drum, whereby the floating heads may move outwardly and effectcommunication between the compression, chamber and the escape passages to relieve an excessive pressure developed within the compression chamber., y

6. In a rotary compressor, the combination of a cylinder, a rotary drum eccenl trically mounted therein and co-operating with the cylinder to form a compression chamber, means for admitting a fluid to said compression chamber, floating heads disposed against the ends of the drum and constituting the end walls of the compression chamber, said compressor. having escape passages constituting recewmg chambers for receiving the fluid under pressure on the Aouter sides of said floating heads, the fluid pressure in .said receiving chambers o .erating to hold the floatingi heads yiel ingly against the ends of the r floating heads mayfmove outwardly to reum, whereby the' f against the ends of the drum before the duidv pressurehas been developed.

7. :in a rotary compressor, the combination of a cylinder mounted to rotate, a drum eccentrically mounted therein, engaging the wall of the cylinder, said cylinder and drum co-operating to form a compression chami ber, means for admitting a fluid to said compression chamber, floating heads rotating with the drum and cylinder, disposed against the ends of the drum and .constituting the end wallsof the compression chamber, said compressor having receivlng chambers on the outer sides of said floating heads for receiving the duid under pressure, the duid .-ressure' in said receiving chambers operatlng to hold thefloating heads yieldingly against the ends of the drum, whereby the oating heads may move outwardly to relieve sudden excessive pressure within the cylinder.

8.v ln a fluid compressing apparatus, the combination of a casing, a rotary compressor mounted in said casing,l includinga rotary outer cylinder, means for delivering lu-x bricating oil into said compressor cylinder, a vbasin within the casing located substantially in the plane of revolution of said compressor whereby the lubricatingoil is throwno' by centrifugal torce from the compressor and accumulates in 'the basin, and a by-pass for leading the 'oil back from the basin to the compressor.

9. En a fluid compressing apparatus, the combination of a casing having an intake port for the duid to be compressed,.a rotary compressor in said casing including a rotary cylinder, said casing having bearings for said compressor, means for supplyin lubricating oil to the bearings and to t e said rotary cylinder, a basin having an outlet and located in a position to catch theoil thrown od from the rotary parts, a by-pass v,'leadin rom'said outlet to said intake port,

\ `to the titl where y, when the compressor is running 'at lits normal speed, the oil fills the by-pass enabling fluid pressure to be developed in the compressor, said basinL having an overow edge substantially on a level with the upper edge of said outlet, whereby, instopping the compressor as soon as the normal speed ot the compressor is reduced, the by-pass opens assa e of the compressed duid and stops t e de ivery of the compressed fluid trom the casing to the reservoir. v

10. lln a kduid compressing apparatus, a casing, a rotar compressor within said cas- -inghaving a s aft with a longitudinal bore operating as an intake duct for the luid to .be compressed, and a diaphragm mounted insaid bore separating the duct fromk the intenso i delivery space of the compressor containing the compressed duid and operating as a safety device to blow out if the pressure on the delivery side of the compressor rises above a predetermined point.

ll. ln a fluid compressing apparatus, thev combination of a casing having an intake port for the fluid to be compressed@ rotary compressor mounted in said casing including a rotary cylinder, a rotary drum mounted in said cylinder, said' casing having bearings for said drum and for said cylinder, means for supplying lubricating oil to the interior of said cylinder, said cylinder having outlet openings for the compressed fluid and lubricating oil llocated so as to pass the compressed duid and lubricating oil over the bearings, means located substantially in the plane of rotation ofthe cylinder for catching; l

the oil thrown from the same by centrifugal force, and means for returning the oil to the intake port.

l2. ln a rotary compressor, the combination of a casing, compressor parts mounted to rotate within said casing and adapted to throw the oil by centrifugal torce against the wall of the casing,'a cup projecting from the wall of the casin to catch the oil, moving by centrifugal orce along the surface or .the wall of the casing, and means for returning the oil to lubricate the rotating parts..

. v13. In a rotary compressor, the combina,-v

tion onta casing, a shaft within said casing, compressor parts driven at a high rotative speed by said shaft whereby the lubricating o l is thrown by centrifugal torce away from the shaft, and meansor delivering the oompressed fluid substantiall' on the axis o the shaft whereby the centri ugal force operates to effect a separation of the lubricating oil from the compressed duid.

le. 'Qn a rotary compressor, the combination ot a casing, a hollow shaft lwithin said casing, compressor parts driven at a high rotative speed b 'said shaft whereby the lubricating oil` 1s thrown by centrifugal force away from the shaft, said shaft having ,air outlets for conductin the cpmpressed duid into the hollow s aft, and a its lll() delivery head on said casing to which4 the hollow shaft delivers the compressed fluid.

15. in a Huid compressing apparatus, a casing, a rotary compressor within said cas. ing having a shaft with a longitudinal bore,

va portion of said bore constituting an intake duct for the luid to be compresse .the other portion or the said bore constituting an outlet duct for the compressed fluid, and adiaphragm mounted in said bore separating` said ducts and operatingA as a safety device to blow out and relieve the-compressor from a dan crous pressure.

16. n a duid compressing apparatuathe' combination of a casing having afstuing vings throu h the wall thereof at said stu box for a box, a rotary compressor within said casing,

an intake duct for leading the iiuid into thel compressor, said shaft havingintake o enitting the Huid into the intake duct, another part of said bore constitutin an outlet duct for leading out the compresse fluid, means within said bore for separating -said ducts'from each other, and means for effecting a circulation of 4oil through said stuiiin box vand through the intake duct,

into t e compressor.

17. In a Huid compressing apparatus, the combination of a casing comprising a body and a pair of heads attached to the ends of said body, a shaft rotatably mounted in said heads, a drum carried by said shaft, each of said heads having a bore eccentric tol theax-is of the shaft, an eccentric mounted in .said bores and having bearings eccentric to' the axis of said shaft, a rotal cylinder comprising a cylinder-shell and' eads rotatably mounted in said lastnamed bearings, and `means for adjusting thel position of said eccentric to re ulate the Contact of the drum with the cylin er-shell.

18: In a iluidcomfpressing apparatus the combination of acylinder-shell, fa rotary drum eccentrically mounted in the sheland cooperating therewith to' form aqcompres- `sion chamber, relief heads disposed against the ends of the drum and shell and constitutin the end walls of the compression cham er, and means for developin a dii'erential effective pressure on the si yes ofthe relief headsto hold the same against the ends `of the cylinder and drum, andto prelvent leakage past'the heads, of the fluid \be ing compressed. t y' In testimony whereof, I have hereunto set my hand. l v

WALTER e. n ROLAFF. 

